I just bought a used 2005 XLT from Hertz car sales (great deals!) and added a stainless steel Tru Filter and put in Mobil 1 5W-20 as specified. I'm curious about the new Mobil 1 oils rated for various mileages. In any case, my mechanic, whom I trust greatly, said that he gets A LOT of cars brought in with engine damage due to the wrong viscosity/weight oil used.